The number of workers over age 55 is expected to increase from 19.2 million in 2002 to 31.8 million by 2015 (GAO Report, 2003). Given these projected increases, the development and testing of cost-effective health promotion interventions for this population is an urgent national priority. If we can reach older adults while they are still working and engage them successfully in sustained health promotion activities, we may be able to make a major impact on future health care expenditures. This project addresses this urgent problem by testing the comparative cost effectiveness of two evidence-based health promotion/ behavior change interventions. The first intervention, the COACH program, uses individualized telephone reinforcement to bolster adherence. The second, the RealAge program, is totally web-based. Both programs administer standardized risk assessments, develop risk profiles, and provide a set of choices for older adult workers with respect to health behavior Action Plans to address improved diet/nutrition, physical activity, and smoking cessation. At present, the comparative appeal of these two approaches and their comparative cost-effectiveness is unknown. The proposed study will test the cost-effectiveness of the two interventions with support staff 50-59 years of age at a major inner city Midwest University using a randomized clinical trial design with 450 participants. Consenting participants will be randomly assigned to a COACH group, a RealAge group, or a health education control group. Process data on intervention use and adherence to Action Plans will be collected. Measures that will be collected at baseline, six, and 12 months include mediators, primary, and secondary outcomes. Mediating variables include stages of readiness for and self-efficacy for specific behavior changes, primary outcomes include health care use and cost, absenteeism, and disability days, and secondary outcomes include vitality, depression, quality of life, blood pressure, and BMI. Cost-effectiveness will be assessed by subtracting program costs from savings obtained in health care utilization and gains in short, intermediate, and long term quality of life adjusted years.